Parents' intention to vaccinate their child for COVID-19: a cross-sectional survey (CoVAccS - wave 3) (preprint)

ObjectivesTo investigate UK parents vaccination intention at a time when COVID-19 vaccination was available to some children. Study designData reported are from the second wave of a prospective cohort study. MethodsOnline survey of 270 UK parents (conducted 4-15 October 2021). At this time, vaccination was available to 16- and 17-year-olds and had become available to 12- to 15- year-olds two weeks prior. We asked participants whose child had not yet been vaccinated how likely they were to vaccinate their child for COVID-19. Linear regression analyses were used to investigate factors associated with intention. Parents were also asked for their main reasons behind vaccination intention. Open-ended responses were analysed using content analysis. ResultsParental vaccination intention was mixed (likely: 39.3%, 95% CI 32.8%, 45.7%; uncertain: 33.9%, 27.7%, 40.2%; unlikely: 26.8%, 20.9%, 32.6%). Intention was associated with: parental COVID-19 vaccination status; greater perceived necessity and social norms regarding COVID-19 vaccination; greater COVID-19 threat appraisal; and lower vaccine safety and novelty concerns. In those who intended to vaccinate their child, the main reasons for doing so were to protect the child and others. In those who did not intend to vaccinate their child, the main reason was safety concerns. ConclusionsParent COVID-19 vaccination and psychological factors explained a large percentage of the variance in vaccination intention for ones child. How fluctuating infection rates, more children being vaccinated, and the UKs reliance on vaccination as a strategy to live with COVID-19 may impact parents intention to vaccinate their child requires further study.

A systematic review of observational methods used to quantify personal protective behaviours among members of the public during the COVID-19 pandemic, and the concordance between observational and self-report measures in infectious disease health protection (preprint)

Objectives: To assess the quantity and quality of studies using an observational measure of behaviour during the COVID-19 pandemic, and to narratively describe the association between self-report and observational data for behaviours relevant to controlling an infectious disease outbreak. Design: Systematic review and narrative synthesis of observational studies. Data sources: We searched Medline, Embase, PsychInfo, Publons, Scopus and the Public Health England behavioural science LitRep database from inception to 17th September 2021 for relevant studies. Study selection: We included studies which collected observational data of at least one of three health protective behaviours (hand hygiene, face covering use and maintaining physical distance from others (social distancing) during the COVID-19 pandemic. Studies where observational data were compared to self-report data in relation to any infectious disease were also included. Data extraction and synthesis: We evaluated the quality of studies using the NIH quality assessment scale for observational studies, extracted data on sample size, setting and adherence to health protective behaviours, and synthesized results narratively. Results: Of 27,279 published papers on COVID-19 relevant health protective behaviours that included one or more terms relating to hand hygiene, face covering and social distancing, we identified 48 studies that included an objective observational measure. Of these, 35 assessed face covering use, 17 assessed hand hygiene behaviour and seven assessed physical distancing. The general quality of these studies was good. When expanding the search to all infectious diseases, we included 21 studies that compared observational versus self-report data. These almost exclusively studied hand hygiene. The difference in outcomes was striking, with self-report over-estimating observed adherence by up to a factor of five in some settings. In only four papers did self-report match observational data in any domains. Conclusions: Despite their importance in controlling the pandemic, we found remarkably few studies assessing protective behaviours by observation, rather than self-report, though these studies tended to be of reasonably good quality. Observed adherence tends to be substantially lower than estimates obtained via self-report. Accurate assessment of levels of personal protective behaviour, and evaluation of interventions to increase this, would benefit from the use of observational methods.

Learning about COVID-19 across borders: Public health information and adherence among international travellers to the UK (preprint)

ObjectivePublic health control measures at borders have long been central to national strategies for the prevention and containment of infectious diseases. Travel was inevitably associated with the rapid global transmission of COVID-19. In the UK, public health authorities took action to reduce risks of travel-associated spread by providing public health information at ports of entry. This study aims to understand individual risk assessment processes, decision making, and adherence to official advice among international travellers; to provide evidence to inform future policy on the presentation of public health information to facilitate safer international travel. Study designThis study is a qualitative study evaluation. MethodSemi-structured interviews were conducted to investigate risk assessment processes, decision making, and adherence to official Public Health England (PHE) advice among travellers. ResultsParticipants regarded official advice as adequate at the time, despite observing differences between the intervention measures implemented in the countries of departure. Participants however also described adopting precautionary measures including self-isolation and the use of face coverings that went beyond official advice, and variability in the extent to which they adhered to guidance on contacting health authorities. Adherence to official guidance was informed by the perceived salience of specific transmission possibilities and containment measures assessed in relation to participants social and institutional environments. ConclusionAnalysis of travellers reported motivations demonstrates that responses to public health advice constitute a proactive process of risk assessment and rationalised decision-making that incorporates consideration of living situation, trust in information sources, correspondence with cultural logics, and willingness to accept potential risk to self and significant others in guiding preventive action. Our findings concerning international passengers understanding of, and compliance with, official advice and mitigation measures provide valuable evidence to inform future policy and we provide recommendations on the presentation of public health information to facilitate safer international travel. Access to a central source of regularly updated official information would help minimise confusion between different national guidelines. Greater attention to the differentiated information needs of diverse groups in creating future public-facing guidance would help to minimise the uncertainties generated by receipt of generic information.

CoMix: Changes in social contacts as measured by the contact survey during the 1 COVID-19 pandemic in England between March 2020 and March 2021 (preprint)

Background: During the COVID-19 pandemic, the UK government imposed public health policies in England to reduce social contacts in hopes of curbing virus transmission. We measured contact patterns weekly from March 2020 to March 2021 to estimate the impact of these policies, covering three national lockdowns interspersed by periods of lower restrictions. Methods: Data were collected using online surveys of representative samples of the UK population by age and gender. We calculated the mean daily contacts reported using a (clustered) bootstrap and fitted a censored negative binomial model to estimate age-stratified contact matrices and estimate proportional changes to the basic reproduction number under controlled conditions using the change in contacts as a scaling factor. Results: The survey recorded 101,350 observations from 19,914 participants who reported 466,710 contacts over 53 weeks. Contact patterns changed over time and by participants' age, personal risk factors, and perception of risk. The mean of reported contacts among adults have reduced compared to previous surveys with adults aged 18 to 59 reporting a mean of 2.39 (95% CI 2.20 - 2.60) contacts to 4.93 (95% CI 4.65 - 5.19) contacts, and the mean contacts for school-age children was 3.07 (95% CI 2.89 - 3.27) to 15.11 (95% CI 13.87 - 16.41). The use of face coverings outside the home has remained high since the government mandated use in some settings in July 2020. Conclusions: The CoMix survey provides a unique longitudinal data set for a full year since the first lockdown for use in statistical analyses and mathematical modelling of COVID-19 and other diseases. Recorded contacts reduced dramatically compared to pre-pandemic levels, with changes correlated to government interventions throughout the pandemic. Despite easing of restrictions in the summer of 2020, mean reported contacts only returned to about half of that observed pre-pandemic.

Behavioural responses to Covid-19 health certification: A rapid review (preprint)

Background Covid-status certification – certificates for those who test negative for the SARS-CoV-2 virus, test positive for antibodies, or who have been vaccinated against SARS-CoV-2 – has been proposed to enable safer access to a range of activities. Realising these benefits will depend in part upon the behavioural and social impacts of certification. The aim of this rapid review was to describe public attitudes towards certification, and its possible impact on uptake of testing and vaccination, protective behaviours, and crime.Method A search was undertaken in peer-reviewed databases, pre-print databases, and the grey literature, from 2000 to December 2020. Studies were included if they measured attitudes towards or behavioural consequences of health certificates based on one of three indices of Covid-19 status: test-negative result for current infectiousness, test-positive for antibodies conferring natural immunity, or vaccination(s) conferring immunity. Results Thirty-three papers met the inclusion criteria, only three of which were rated as low risk of bias. Public attitudes were generally favourable towards the use of immunity certificates for international travel, but unfavourable towards their use for access to work and other activities. A significant minority was strongly opposed to the use of certificates of immunity for any purpose. The limited evidence suggested that intention to get vaccinated varied with the activity enabled by certification or vaccination (e.g., international travel). Where vaccination is seen as compulsory this could lead to unwillingness to accept a subsequent vaccination. There was some evidence that restricting access to settings and activities to those with antibody test certificates may lead to deliberate exposure to infection in a minority. Behaviours that reduce transmission may decrease upon health certificates based on any of the three indices of Covid-19 status, including physical distancing and handwashing.Conclusions The limited evidence suggests that health certification in relation to COVID-19 – outside of the context of international travel – has the potential for harm as well as benefit. Realising the benefits while minimising the harms will require real-time evaluations allowing modifications to maximise the potential contribution of certification to enable safer access to a range of activities. 

Engagement with daily testing instead of self-isolating in contacts of confirmed cases of SARS-CoV-2. (preprint)

BackgroundIn December 2020, Public Health England with NHS Test and Trace initiated a pilot study in which close contacts of people with confirmed COVID-19 were given the option to carryout lateral flow device antigen tests at home, as an alternative to self-isolation for 10-14 days. In this study, we evaluated acceptability of and engagement with daily testing, and assessed levels of adherence to the rules relating to behaviour following positive or negative test results. MethodsWe conducted a service evaluation of a pilot study, involving an online cross-sectional survey offered to adult (> 18 years) contacts of confirmed COVID-19 cases who were invited to participate in seven days of daily testing instead of isolation. We used a comparison group of contacts who were not offered testing and performed self-isolation. Herein, we examine survey responses from a subset of those who took part in the pilot study and who responded to the evaluation questionnaire. ResultsAcceptability of daily testing was lower among survey respondents who were not offered the option of having it and among people from ethnic minority groups. Overall, 52% of respondents reported being more likely to share details of people that they had been in contact with following a positive test result, if they knew that their contacts would be offered the option of daily testing. Only 2% reported that they would be less likely to provide details of their contacts. On the days that they were trying to self-isolate, 19% of participants reported that they left the house, with no significant demographic group differences. Following a negative test, 13% of respondents reported that they increased their contacts, but most (58%) reported having fewer risky contacts. ConclusionsOur data suggest that daily testing is potentially acceptable, and may facilitate sharing contact details of close contacts among those who test positive for COVID-19, and promote adherence to self-isolation. A better understanding is needed of how to make this option more acceptable for all households. The impact of receiving a negative test on behaviour remains a risk that needs to be monitored and mitigated by appropriate messaging. Future research should examine attitudes and behaviour in a context where infection levels are lower, testing is more familiar, much of the population has been vaccinated and restrictions on activity have been reduced.

Experiences of supported isolation in returning travellers during the early COVID-19 response: an interview study (preprint)

ObjectivesTo understand the experiences of those who underwent supported isolation as part of the response to the COVID-19 pandemic, after returning to the UK from Wuhan, China. DesignWe used semi-structured interviews to capture participants experiences and perceptions of supported isolation. SettingTelephone interviews carried out within approximately one month of an individual leaving supported isolation. Participants26 people who underwent supported isolation at either Arrowe Park Hospital (n = 18) or Kents Hill Park Conference Centre (n = 8) after being repatriated from Wuhan in January - February 2020. ResultsParticipants were willing to undergo supported isolation because they understood that it would protect themselves and others. Positive treatment by staff was fundamental to participants willingness to comply with isolation procedures. Despite the high level of compliance, participants expressed some uncertainty about what the process would involve. ConclusionsAs hotel quarantine is introduced across the UK for international arrivals, our findings suggest that those in charge should: communicate effectively before, during and after quarantine, emphasising why quarantine is important and how it will protect others; avoid enforcement and focus on supporting and promoting voluntary compliance; facilitate shared social experiences for those in quarantine; and ensure all necessary supplies are provided. Doing so will increase adherence and reduce any negative effects on wellbeing.

Intention to have the seasonal influenza vaccination during the COVID-19 pandemic among eligible adults in the UK (preprint)

We investigated likelihood of having the seasonal influenza vaccination in 645 participants who were eligible for the vaccination in the UK. 55.8% indicated they were likely to have the vaccination. Previous research suggests that increasing uptake of the influenza vaccination may help contain a COVID-19 outbreak, so steps need to be taken to convert intention into behaviour and to reach the 23.9% who were unlikely to have the vaccination and the 20.3% who were unsure.

Public health information on COVID-19 for international travellers: Lessons learned from a rapid mixed-method evaluation in the UK containment phase (preprint)

Introduction In the containment phase of the response to the COVID-19 outbreak, Public Health England (PHE) delivered advice to travellers arriving at major UK ports. We aimed to rapidly evaluate the impact and effectiveness of these communication materials for passengers in the early stages of the pandemic. Methods In stage I (Patient and Public Involvement, PPI) we interviewed seven travellers who had returned from China in January and February 2020. We used these results to develop a questionnaire and topic guides for stage II, a cross-sectional survey and follow-up interviews with passengers arriving at London Heathrow Airport on scheduled flights from China and Singapore. The survey assessed passengers' knowledge of symptoms, actions to take and attitudes towards PHE COVID-19 public health information; interviews explored their views of official public health information and self-isolation. Results In stage II, 121 passengers participated in the survey and 15 in follow-up interviews. 83% of surveyed passengers correctly identified all three COVID-19 associated symptoms listed in PHE information at that time. Most could identify the recommended actions and found the advice understandable and trustworthy. Interviews revealed that passengers shared concerns about the lack of wider official action, and that passengers' knowledge had been acquired elsewhere as much from PHE. Respondents also noted their own agency in choosing to self-isolate, partially as a self-protective measure. Conclusion PHE COVID-19 public health information was perceived as clear and acceptable, but we found that passengers acquired knowledge from various sources and they saw the provision of information alone on arrival as an insufficient official response. Our study provides fresh insights into the importance of taking greater account of diverse information sources and of the need for public assurance in creating public health information materials to address global health threats. Keywords COVID-19, public health advice, government, policy, airport, international travel

COVID-19 vaccination intention in the UK: Results from the COVID-19 Vaccination Acceptability Study (CoVAccS), a nationally representative cross-sectional survey (preprint)

Aim: To investigate factors associated with intention to be vaccinated against COVID-19. Methods: Online cross-sectional survey of 1,500 UK adults, recruited from an existing online research panel. Data were collected between 14th and 17th July 2020. We used linear regression analyses to investigate associations between intention to be vaccinated for COVID-19 when a vaccine becomes available to you and socio-demographic factors, previous influenza vaccination, general vaccine attitudes and beliefs, attitudes and beliefs about COVID-19, and attitudes and beliefs about a COVID-19 vaccination. Results: 64% of participants reported being likely to be vaccinated against COVID-19; 27% were unsure and 9% reported being unlikely to be vaccinated. Personal and clinical characteristics, previous influenza vaccination, general vaccination beliefs, and beliefs and attitudes about COVID-19 and a COVID-19 vaccination explained 77% of the variance in vaccination intention. Intention to be vaccinated was associated with more positive general COVID-19 vaccination beliefs and attitudes, weaker beliefs that the vaccination would cause side effects or be unsafe, greater perceived information sufficiency to make an informed decision about COVID-19 vaccination, greater perceived risk of COVID-19 to others but not oneself, older age, and having been vaccinated for influenza last winter (2019/20). Conclusions: Despite uncertainty around the details of a COVID-19 vaccination, most participants reported intending to be vaccinated for COVID-19. Actual uptake will likely be lower. Vaccination intention reflects general vaccine beliefs and attitudes. Campaigns and messaging about a COVID-19 vaccination should emphasize the risk of COVID-19 to others and necessity for everyone to be vaccinated.

Adherence to protective measures among health care workers in the UK; a cross-sectional study (preprint)

Healthcare workers (HCWs) are frontline responders to emergency infectious disease outbreaks such as COVID-19. We investigated factors associated with adherence to personal protective behaviours in UK HCWs during the COVID-19 pandemic using an online cross-sectional survey of 1035 healthcare professionals in the UK. Data were collected between 12th and 16th June 2020. Adjusted logistic regressions were used to separately investigate factors associated with adherence to use of personal protective equipment, maintaining good hand hygiene, and physical distancing from colleagues. Adherence to personal protective measures was suboptimal (PPE use: 80.0%, 95% CI [77.3 to 82.8], hand hygiene: 67.8%, 95% CI [64.6 to 71.0], coming into close contact with colleagues: 74.7%, 95% CI [71.7 to 77.7]). Adherence to PPE use was associated with having adequate PPE resources, receiving training during the pandemic, lower perceived fatalism from COVID-19, higher perceived social norms and higher perceived effectiveness of PPE. Adherence to physical distancing was associated with one's workplace being designed, using markings to facilitate physical distancing and receiving training during the pandemic. There were few associations with adherence to hand hygiene. Findings indicate HCWs should receive training on personal protective behaviours to decrease fatalism over contracting COVID-19 and increase perceived effectiveness of protective measures.

Factors associated with self-reported anxiety, depression, and general health during the UK lockdown; a cross-sectional survey (preprint)

Background: To investigate factors associated with anxiety, depression, and self-reported general health during "lockdown" due to COVID-19 in the UK. Methods: Online cross-sectional survey of a nationally-representative sample of 2240 participants living in the UK aged 18 years or over (data collected 6-7 May 2020). Participants were recruited from YouGov's online research panel. Outcomes: In this sample, 21.9% (n=458, 95% CI [20.1% to 23.7%]) reported probable anxiety (scored three or over on the GAD-2); while 23.5% (n=494, 95% CI [21.7% to 25.3]) reported probable depression (scored three or over on the PHQ-2). Poorer mental health was associated with greater financial hardship during the lockdown, thinking that you would lose contact with friends or family if you followed Government measures, more conflict with household members during the lockdown, less sense of community with people in your neighbourhood, and lower perceived effectiveness of Government measures. Females and those who were younger were likely to report higher levels of anxiety and depression. The majority of participants reported their general health as "good" (as measured by the first item of the SF-36). Poorer self-reported general health was associated with psychological distress, greater worry about COVID-19 and markers of inequality. Interpretation: Rates of self-reported anxiety and depression in the UK during the lockdown were greater than population norms. Reducing financial hardship, promoting social connectedness, and increasing solidarity with neighbours and household members may help ease rifts within the community which are associated with distress, thereby improving mental health. Reducing inequality may also improve general health.

Factors associated with adherence to self-isolation and lockdown measures in the UK; a cross-sectional survey (preprint)

Objectives: To investigate factors associated with adherence to self-isolation and lockdown measures due to COVID-19 in the UK. Design: Online cross-sectional survey. Setting: Data were collected between 6th and 7th May 2020. Participants: 2240 participants living in the UK aged 18 years or over. Participants were recruited from YouGov's online research panel. Main outcome measures: Having gone out in the last 24 hours in those who reported symptoms of COVID-19 in their household. Having gone out shopping for items other than groceries, toiletries or medicines (non-essentials), and total number of outings, in the last week in those who reported no symptoms of COVID-19 in their household. Results: 217 people (9.7%) reported that they or someone in their household had symptoms of COVID-19 (cough or high temperature / fever) in the last seven days. Of these people, 75.1% had left the home in the last 24 hours (defined as non-adherent). Factors associated with non-adherence were being male, less worried about COVID-19, and perceiving a smaller risk of catching COVID-19. Adherence was associated with having received help from someone outside your household. Results should be taken with caution as there was no evidence for associations when controlling for multiple analyses. Of people reporting no symptoms in the household, 24.5% had gone out shopping for non-essentials in the last week (defined as non-adherent). Factors associated with non-adherence and with a higher total number of outings in the last week included decreased perceived effectiveness of Government "lockdown" measures, decreased perceived severity of COVID-19, and decreased estimates of how many other people were following lockdown rules. Having received help was associated with better adherence. Conclusions: Adherence to self-isolation is poor. As we move into a new phase of contact tracing and self-isolation, it is essential that adherence is improved. Communications should aim to increase knowledge about actions to take when symptomatic or if you have been in contact with a possible COVID-19 case. They should also emphasise the risk of catching and spreading COVID-19 when out and about and the effectiveness of preventative measures. Using volunteer networks effectively to support people in isolation may promote adherence.

Factors affecting healthcare workers' compliance with social and behavioural infection control measures during emerging infectious disease outbreaks: Rapid evidence review. (preprint)

The 2019-2020 outbreak of novel coronavirus has raised concerns about nosocomial transmission; that is, transmission within healthcare settings. Research from previous outbreaks of emerging infectious diseases suggests a major cause of nosocomial transmission is healthcare professionals' poor compliance with recommended personal protective behaviours. This rapid evidence review explored existing literature on emerging infectious disease outbreaks to identify factors associated with compliance with social and behavioural infection control measures among healthcare staff. 56 papers were reviewed and several positive associations were found: Staff working in emergency or intensive care settings appeared more likely to comply with recommendations than those in other settings, and there was some evidence that contact with confirmed cases could improve compliance. There was some evidence that staff with higher levels of anxiety and higher concern about the risk of infection were more likely to comply with recommended behaviour, and that monitoring from superiors could improve compliance. Several negative associations were also found. Observed non-compliance of colleagues could hinder compliance. Staff identified many barriers to compliance related to personal protective equipment, including availability; perceived difficulty and effectiveness; inconvenience; discomfort; and a negative impact on patient care. There appeared to be many issues regarding the communication and ease of understanding of infection control guidance. Based on the results of this review we recommend provision of training and education tailored for different occupational roles within the healthcare setting; managerial staff 'leading by example'; ensuring adequate resources for infection control; and timely provision of practical evidence-based infection control guidelines.

Immunity Passports for SARS-CoV-2: an online experimental study of the impact of antibody test terminology on perceived risk and behaviour (preprint)

WHAT IS ALREADY KNOWN ON THIS TOPICO_LITest results indicating the presence of antibodies to SARS-CoV-2 are often referred to as Immunity Passports or Certificates. C_LIO_LIDue to the limitations of such tests, including uncertainty about the duration of immunity conferred by detected antibodies, those receiving results indicating the presence of antibodies retain a risk of becoming infected by SARS-CoV-2. C_LIO_LIIt is unknown whether the use of the terms Immunity Passports or Certificates reduces awareness of the residual risk inherent in an antibody-positive test result and adherence to protective behaviours, thereby increasing risk of transmission. C_LI WHAT THIS STUDY ADDSO_LIUsing the term Immunity - as opposed to Antibody - to describe antibody tests for SARS-CoV-2 more than doubled the proportion who erroneously perceived they would have no risk of catching coronavirus in the future given an antibody-positive test result, from 9.8% for Antibody to 19.1% for Immunity. C_LIO_LIPerceiving no risk of infection with coronavirus given an antibody-positive test result was associated with an intention to wash hands less frequently. C_LIO_LIUsing the terms Passport, Certificate or Test had no significant effect. C_LI ObjectiveTo assess the impact of describing an antibody-positive test result using the terms Immunity and Passport or Certificate, alone or in combination, on perceived risk of becoming infected with SARS-CoV-2 and intention to continue protective behaviours. Design2 x 3 experimental design. SettingOnline with data collected between 28th April and 1st May 2020. Participants1,204 adults registered with a UK research panel. InterventionParticipants were randomised to receive one of six descriptions of an antibody test and results showing SARS-CoV-2 antibodies, differing in the terms used to describe the type of test (Immunity vs Antibody) and the test result (Passport vs Certificate vs Test). Main outcome measuresThe primary outcome was the proportion of participants perceiving no risk of becoming infected with SARS-CoV-2 given an antibody positive test result. Other outcomes include intended changes to frequency of handwashing and physical distancing. ResultsWhen using the term Immunity (vs Antibody), 19.1% of participants [95% CI: 16.1 to 22.5] (vs 9.8% [95% CI: 7.5 to 12.4]) perceived no risk of catching coronavirus at some point in the future given an antibody-positive test result (AOR: 2.91 [95% CI: 1.52 to 5.55]). Using the terms Passport or Certificate - as opposed to Test - had no significant effect (AOR: 1.24 [95% CI: 0.62 to 2.48] and AOR: 0.96 [95% CI: 0.47 to 1.99] respectively). There was no significant interaction between the effects of the test and result terminology. Across groups, perceiving no risk of infection was associated with an intention to wash hands less frequently (AOR: 2.32 [95% CI: 1.25 to 4.28]) but there was no significant association with intended avoidance of physical contact with others outside of the home (AOR: 1.37 [95% CI: 0.93-2.03]). ConclusionsUsing the term Immunity (vs Antibody) to describe antibody tests for SARS-CoV-2 increases the proportion of people believing that an antibody-positive result means they have no risk of catching coronavirus in the future, a perception that may be associated with less frequent handwashing. The way antibody testing is described may have implications for the likely impact of testing on transmission rates. Study registrationOpen Science Framework: https://osf.io/tjw78/files/

The impact of believing you have had COVID-19 on behaviour: Cross-sectional survey (preprint)

ObjectivesTo investigate whether people who think they have had COVID-19 are less likely to engage in social distancing measures compared with those who think they have not had COVID-19. DesignOn-line cross-sectional survey. SettingData were collected between 20th and 22nd April. Participants6149 participants living in the UK aged 18 years or over. Main outcome measuresPerceived immunity to COVID-19, self-reported adherence to social distancing measures (going out for essential shopping, nonessential shopping, and meeting up with friends/family; total out-of-home activity), worry about COVID-19 and perceived risk of COVID-19 to oneself and people in the UK. Knowledge that cough and high temperature / fever are the main symptoms of COVID-19. ResultsIn this sample, 1493 people (24.3%) thought they had had COVID-19. Only 245 (4.0%) reported receiving a test result saying they had COVID-19. Reported test results were often incongruent with participants belief that they had had COVID-19. People who believed that they had had COVID-19 were: more likely to agree that they had some immunity to COVID-19; less likely to report adhering to social distancing measures; less worried about COVID-19; and less likely to know that cough and high temperature / fever are two of the most common symptoms of COVID-19. ConclusionsThe number of people in the UK who think they have already had COVID-19 is about twice the rate of current prevalence estimates. People who think that they have had COVID-19 may contribute to transmission of the virus through non-adherence to social distancing measures. Clear communications to this growing group are needed to explain why protective measures continue to be important and to encourage sustained adherence. COPYRIGHTThe Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive licence (or non exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd to permit this article (if accepted) to be published in BMJ editions and any other BMJPGL products and sublicences such use and exploit all subsidiary rights, as set out in our licence. FUNDING SOURCESJW is funded by a career development fellowship from Cancer Research UK (ref C7492/A17219). LS and GJR are supported by the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Emergency Preparedness and Response at Kings College London in partnership with Public Health England (PHE), in collaboration with the University of East Anglia and Newcastle University. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care, Public Health England. Data collection was funded via a block Government grant to the Behavioural Insights Team. COMPETING INTEREST STATEMENTAll authors have completed the Unified Competing Interest form (available on request from the corresponding author) and declare: ALM and ME report grants from government partners to the Behavioural Insights Team, during the conduct of the study, JW reports grants from Cancer Research UK, during the conduct of the study; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work. TRANSPARENCY DECLARATIONThe authors affirm that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as originally planned have been explained. AUTHOR CONTRIBUTION STATEMENTThe study was conceptualised by LS, GJR, JW and TMM. AM and ME completed data collection. LS analysed the data. All authors contributed to, and approved, the final manuscript. WHAT IS ALREADY KNOWN ON THIS TOPICO_LIDuring the COVID-19 pandemic, multiple countries, including the UK, have introduced "lockdown" measures. C_LIO_LIThe World Health Organization has warned against using the results of antibody tests to issue "immunity passports" due to fears that those who test positive for antibodies may stop adhering to protective measures. C_LIO_LIThere is no research investigating adherence to protective measures among those who think they have had COVID-19. C_LI WHAT THIS STUDY ADDSO_LIThis is the first study investigating behavioural differences between those who think they have had COVID-19 and those who do not. C_LIO_LIAbout twice as many people think they have had COVID-19 than prevalence estimates suggest. C_LIO_LIResults suggest that there may be a high degree of self-misdiagnosis within those who think they have had COVID-19. C_LIO_LIThose who think they have had COVID-19 were more likely to think they were immune to COVID-19, and less likely to adhere to social distancing measures. C_LI

Quantifying the impact of physical distance measures on the transmission of COVID-19 in the UK (preprint)

Background: To mitigate and slow the spread of COVID-19, many countries have adopted unprecedented physical distancing policies, including the UK. We evaluate whether these measures might be sufficient to control the epidemic by estimating their impact on the reproduction number (R0, the average number of secondary cases generated per case). Methods: We asked a representative sample of UK adults about their contact patterns on the previous day. The questionnaire documents the age and location of contacts and as well as a measure of their intimacy (whether physical contact was made or not). In addition, we asked about adherence to different physical distancing measures. The first surveys were sent on Tuesday 24th March, one day after a "lockdown" was implemented across the UK. We compared measured contact patterns during the lockdown to patterns of social contact made during a non-epidemic period. By comparing these, we estimated the change in reproduction number as a consequence of the physical distancing measures imposed. We used a meta-analysis of published estimates to inform our estimates of the reproduction number before interventions were put in place. Findings: We found a 73% reduction in the average daily number of contacts observed per participant (from 10.2 to 2.9). This would be sufficient to reduce R0 from 2.6 prior to lockdown to 0.62 (95% confidence interval [CI] 0.37 - 0.89) after the lockdown, based on all types of contact and 0.37 (95% CI = 0.22 - 0.53) for physical contacts only. Interpretation: The physical distancing measures adopted by the UK public have substantially reduced contact levels and will likely lead to a substantial impact and a decline in cases in the coming weeks. However, this projected decline in incidence will not occur immediately as there are significant delays between infection, the onset of symptomatic disease and hospitalisation, as well as further delays to these events being reported. Tracking behavioural change can give a more rapid assessment of the impact of physical distancing measures than routine epidemiological surveillance.